pnpm.fetchDeps: add fetcherVersion to passthru

This way we should be able to write tooling to automatically upgrade
this version in the future.

Signed-off-by: Sefa Eyeoglu <contact@scrumplex.net>

pkgs/development/tools/pnpm/fetch-deps/default.nix

@@ -139,6 +139,7 @@ in
           '';
 
           passthru = {
+            inherit fetcherVersion;
             serve = callPackage ./serve.nix {
               pnpm = args.pnpm or pnpm';
               pnpmDeps = finalAttrs.finalPackage;